Shearing blade mount for cut-off die set

ABSTRACT

A shearing blade assembly specifically for use in a double cut die set of the type used to cut tubing continuously emanating from a tube mill. The present invention is directed toward the shearing blade assembly used in conjunction with the notching blade of the cut-off die set. The subject device includes a mounting block fixed to the upper platen of a die set, a shearing blade mounted to a shearing blade cartridge. The shearing blade cartridge is then inserted into the mounting block and is retained in position by a cam lock assembly. The cam lock assembly and cartridge system allows the shearing blade to be quickly and efficiently removed and replaced as needed.

This is a continuation-in-part of co-pending application Ser. No.255,315 filed on Oct. 11, 1988, now abandoned.

INTRODUCTION

This invention relates to a cut-off die set of the type used incombination with a press to cut tubing and fabricated shapes as they arefabricated. More specifically, the present invention is directed towardimprovements in the shearing blade assembly of a die set whichfacilitate the installation and replacement of the shearing blade.

BACKGROUND OF THE INVENTION

In a cut-off die set, a shearing blade is used to shear a continuouslength of tubing emanating from a tube mill into useful and manageablesections. The shearing apparatus typically comprises a shearing bladefixed or mounted to an upper platen which is mounted on pins formovement relative to a lower platen. As the die set is closed, theshearing blade severs the tubing into predetermined lengths. Both singleand double cut die sets are known.

Presently the upper end of the shearing blade is clamped to a blademounting block fixed to the upper platen of the die set by machinescrews. The blade is contained in a recess on the face of the mountingblock. Spacers of various thicknesses are disposed between the blade andthe mounting block. The spacers are used to align the shearing blade. Aclamping plate is used to fasten the shearing blade to the blademounting block. The clamping plate is fixed to the blade mounting blockby threaded fasteners extending through both the clamping plate andshearing blade. The threaded fasteners are received in threaded boreslocated on the mounting block.

Eventually the cutting surface of the shearing blade becomes dull duringthe cutting operation. When dull, the shearing blade must be sharpenedor replaced in order for the die set to continue operating at maximumefficiency. Changing the shearing blade is a time consuming procedure.The operator is required to loosen and remove the clamping plate andscrews fastening the blade to the mounting block. When the clampingplate is removed the operator must remove the old blade and insert a newblade in the proper position on the mounting block. Finally the operatormust replace the clamping plate and re-tighten the screws therebyfastening the new blade to the mounting block.

The operator must also follow the same time consuming procedure whenchanging the blade to accommodate different sizes of tubing or when theblade is broken during the cutting operation. Any time savings that cangained while changing the shearing blade results in increased operationtime of the mill. As indicated, time is of the essence in the tubecutting industry, tubing continuously emanates from a tube mill at ahigh rate of speed. Thus, any problems, delays or shutdowns due torepair or replacement of the cutting equipment results in lostproduction and revenue to the tube maker. Therefore, any time savingsthat results from ease in maintenance and/or replacement of partsincreases the period the mill can be operational, thus increasingproduction.

SUMMARY OF THE INVENTION

The present invention is directed to an improved mounting means for theshearing blade of a cut-off die set. According to the invention amounting block having front and rear members separated by a downwardopening gap is mounted to the upper platen of a cut-off die set. Ashearing blade cartridge including a back plate and clamp member whichsandwich the shearing blade therebetween is positioned in the downwardlyopening gap. A wedge member is urged into contact with the bladecartridge by an eccentric to secure the blade cartridge in the mountingblock.

A further aspect of the invention includes a retaining member projectingoutward from the blade cartridge which engages a complementary retainingnotch on the mounting block to further secure the blade cartridge withinthe mounting block.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an end view of the first embodiment of cut-off die setaccording to the invention;

FIG. 2 is a section view of the die set taken along section line 2--2;

FIG. 3 is an exploded perspective view of the first embodiment of theshearing blade mounting structure;

FIG. 4 is another exploded perspective view of the first embodimentmeans for mounting the shearing blade cartridge mounting block;

FIG. 5 is an exploded perspective view of the second embodiment formounting the shearing blade cartridge;

FIGS. 6a and 6b are side views of the eccentric portion of the eccentricmember and wedge member in cooperation with the blade cartridge; and

FIG. 7 is a perspective view of the wedge member and retaining membercombination.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The illustrated cut-off die set 10 is adapted to be employed in a tubecutting press (not shown) and is slidably movable along a set of rails11 which are part of the press base. The press includes a swinging orreciprocating ram mechanism (not shown) which bears against an upperplaten 12 and serves to operate the cut-off die set 10. In die sets ofthe general type with which the present invention is concerned, thecut-off die set is positioned to receive the tubing as it emanates fromthe fabrication mill and the ram mechanism operates to cause theclamping jaws within the die set to clamp the die set to the rapidlymoving tubing. The die set, clamped to the moving tube, moves togetherwith the tube along the rails 11. The ram mechanism then causes thenotching blade to make a notching cut in the upper periphery of thetubing whereafter the shearing blade is lowered to sever a length fromthe moving tube. Following the final severing cut, the ram mechanism,then operating in a reverse manner, first causes retraction of theshearing blade and the notching blade and then unclamping of the die setfrom the tube section as the cut-off die set approaches the end of itstravel on the rails 11. The cut-off die set is then returned to itsinitial position on the rails set 11 preparatory to initiation of a newcut-off cycle. This description of a flying, double cut operationnotwithstanding, the invention is also useful in stationary cut andsingle cut applications.

Cut-off die set 10 includes an upper platen 12 and a lower platen 14.

Upper platen 12 overlies the tube path 16 and includes three guide rods18, 20 and 22 extending downwardly from spaced locations on theunderside of platen 12. Guide rod 18 is positioned on the left-hand ornear side of tube path 16 and guide rods 20 and 22 are positioned at thefront and rear of the cut-off die set respectively on the right-hand orremote side of tube path 16. A die jaw cam 24 extends downwardly fromupper platen 12 generally between guide rods 20 and 22 and a cam guide26 extends downwardly from upper platen 12 adjacent the rear edgethereof and on the near or left-hand side of tube path 16.

A plurality of guide sleeves or bushings 28, 30 and 32 upstand fromlower platen 14 and respectively telescopically receive the lower endsof guide rods 18, 20 and 22 so as to guide upper platen 12 in reciprocalmovement relative to lower platen 14 during the tube severing operation.

The tubing 34 emanating from the tube forming mill is clamped to the dieset 10 by means of two pairs of die jaws 36 and 38 each having acomplementary inner radius contour 40 and 42, conforming to the tubecontour. The reciprocal clamping and disengaging movement of die jaws 36and 38 is produced by sliding movement of an upper die jaw holder 44 anda lower die jaw holder 46 slidable on each other. The die clamping jaws36 and 38 are adapted to be reciprocated towards and away from eachother in synchronism with the movement of the upper platen relative tothe lower platen by coaction of die jaw cam 24 passing between a pair ofclamping rollers 48 and 50 carried respectively by the upper die jawholder 44 and lower die jaw holder 46. The manner in which the cam 24coacts with the rollers 48 and 50 to move the die jaws 36 and 38 intoand out of clamping engagement with tube 34 will not be furtherdescribed since this mechanism is known and is not part of the presentinvention. Further details of a mechanism of this type may be found inU.S. Pat. Nos. 4,108,029 and 4,294,147, both assigned to the assignee ofthe subject application, disclosures of which are incorporated herein byreference.

A notching assembly seen generally at 56, having a notching blade holder52 and a notching blade 54 operates to provide a notching cut in theupper periphery of the tube prior to the downward severing movement ofthe shearing blade. The notching cut precludes the necessity of furtherworking of the severed tube section following the severing operation.Both thrust and "pull across" notching assemblies are known; see, forexample U.S. Pat. Nos. 4,109,555 and 4,294,147, respectively,disclosures of which are herein incorporated by reference.

Notching assembly 56 is supported on a cross slide assembly 68comprising a support bracket 58, a support bracket 60, a support bracket62, an upper guide shaft 64 and a lower guide shaft 66. A cam follower27 is fixed to the cross slide 68 and follows cam guide 26 having acurvilinear cam track 26a. Movement of the upper platen 12 causes thecam guide 26 to impart reciprocal motion 69 to the cross slide 68.Further details of a cross slide mechanism of this type may be found inU.S. Pat. No. 4,766,792, assigned to the assignee of the subjectapplication, disclosure of which is herein incorporated by reference.

FIGS. 3 and 4 illustrate the first embodiment of the shearing bladeassembly. A mounting block 84 is fixed to the upper platen 12 of the dieset 10. Threaded fasteners extending through bores 12a are threadablyreceived in bores 84a located on the mounting block 84. While threadedfasteners are herein used to fix mounting block 84 to upper platen 12,other fastening means such as riveting, welding, or brazing could beused to fix mounting block to upper platen 12. If so desired, block 84could be formed as an integral part of platen 12. Mounting block 84 hasa slot 84c existing normal to the tube path 16, slot 84c is ofsufficient size to receive the shearing blade cartridge assembly 69.

The shearing blade 70 is mounted within the shearing blade cartridge 72by means of threaded fasteners 76 extending through transverse bores 72aand threadably received in the clamping plate 74. Although threadedfasteners are used herein, other fastening means could also be used tofix the shearing blade 70 to the blade cartridge 72, such as rivets,welds or brazing. If desired, the total blade cartridge could beintegrally formed, thus eliminating the use for any type of fasteningmeans. The shearing blade 70 is made of a high speed steel having asharpened cutting surface opposite the blade cartridge.

A change in the size or the wall thickness of the tubing 34 being cutnecessitates that different sizes of shearing blade to be used toproperly sever the tubing 34. A spacer plate 86 is used in combinationwith the clamping plate 74 to properly retain the shearing blade 70 inthe blade cartridge 72. The spacer plate 86 allows a standard size bladecartridge 72 to be used with different sizes of shearing blade 70.Obviously when changing the width and/or thickness of the shearingblade, different shapes, sizes or combinations of spacer plates 86 areneeded to fix the shearing blade 70 in the proper position on theshearing blade cartridge 72.

The blade cartridge 72 is held in position in the mounting block 84 bymeans of a V-shaped gib 78 fixed to the mounting block 84. A cam lockassembly 82 is used to urge the blade cartridge 72 against the gib 78.The blade cartridge 72 has a corresponding V-shaped projection 72cadapted to be received in the complementary V-shaped notch 78c existingon the gib 78. The gib 78 is fixedly mounted to the mounting block 84 bymeans of threaded fasteners extending through transverse bores 78a andthreadably received in threaded bores 84d located on mounting block 84.The gib 78 is also aligned and fixed to mounting block 84 by means ofdowel pins 86 extending through transverse bores 78b and received inbores 84e located on mounting block 84.

A dowel pin 80 extends through bore 78c existing on gib 78. The dowelpin 80 forms a projection which is received in a complementary notch 72blocated on the V-shaped bearing surface 72c of the blade cartridge 72.When the blade cartridge 72 is fixed in the cutting position, thecombination of dowel pin 80 and notch 72b act to prevent the blade frombeing pulled out of the mounting block should the blade encounter anyobstructions or binding action when the die set is being operated in thereciprocal manner, i.e. when the shearing blade is being retracted aftersevering the tubing.

The cam lock assembly 82 used to urge the V-shaped projection 72c of theblade cartridge into the V-shaped notch 78c of the gib 78 includes ashaft 82a extending through a transverse bore 84b located on mountingblock 84. The cam lock assembly further includes an eccentric 82b fixedto the shaft 82a. The cam lock assembly is locked in the fixed positionby a nut 82c adapted to be received on the threaded portion of the shaft82a.

The first embodiment allows the shearing blade 70 to be mounted in theblade cartridge 72, thus forming a shearing blade and cartridge assembly69. The shearing blade cartridge assembly 69 is then inserted into themounting block 84 engaging the bearing surface 72c against thecomplementary bearing surface of the gib 78c, further engaging notch 72bwith dowel pin 80. The cam lock assembly 82 is then rotated to lock thecartridge assembly 69 in a fixed position. When the blade cartridgeassembly 69 needs to be removed, the operator need only loosen the camlock assembly 82 enabling the operator to remove the blade cartridgeassembly 69 from the mounting block 84.

FIGS. 5-7 illustrate the second embodiment of the shearing bladeassembly. Mounting block 86 is fixed to the upper platen 12 of the dieset 10. Threaded fasteners extending through bores on the upper platenare threadably received in bores 86a located on the mounting block 86.While threaded fasteners are herein used to fix mounting block 86 toupper platen 12, other fastening means such as riveting, welding orbrazing could be used to fix the mounting block to the upper platen 12.Mounting block 86 could be formed as an integral part of platen 12. Themounting block is U-shaped having legs 86b and 86c and a base portion86d. The leg portions 86b and 86c are parallel to the tube path 16. Theshearing blade 88 is mounted in the shearing blade cartridge 90 by meansof threaded fasteners extending through the clamping plate 92 andthreadably received in the blade cartridge 90. Although threadedfasteners are used herein, other fastening means could also be used toaffix the shearing blade 88 to the blade cartridge 90 such as rivets,welds or brazing. If desired, the total blade cartridge could beintegrally formed, thus eliminating the use for any type of fasteningmeans. The blade cartridge 90 has an upper outward projection 90a whichcoacts with the ledge portion 86e of the mounting block 86.

The blade cartridge 90 is held in position in the mounting block 86 bymeans of a wedge member 94 coacting with a retaining member 96 which isconnected to the mounting block 86 by means of threaded fasteners.Obviously other fastening means could be used. The wedge member 94 has aplanar face parallel to the blade cartridge 90. The face opposite saidplanar face is inclined and coacts with a complementary inclined orbeveled surface on the retaining member 96. The wedge member has an ovalbore 94a located therein. An eccentric member 98 is placed within thebores 96a of the retaining member 96 and 86f of the mounting block 86.The eccentric member 98 has an eccentric portion 98a which coacts withthe slotted bore 94a of the wedge member 94. A locking nut 100 is placedon the threaded portion 98b of the eccentric member 98 and is used tolock the eccentric member in a fixed position.

Referring now to FIG. 6a, FIG. 6a shows the wedge member 94 in theunlocked or unengaged position, as shown the eccentric portion 98a ofthe eccentric 98 has been rotated to the upward position thereby causingthe wedge member 94 to be disengaged from the blade cartridge 90.

FIG. 6b shows the wedge member 94 in a locked position as the eccentricportion 98a of the eccentric 98 has been rotated downward to force thewedge member along the inclined surface of the retaining member 96,thereby creating a wedging force and clamping the blade cartridge 90 inthe mounting block.

Referring now to FIG. 7, FIG. 7 shows a perspective view of theeccentric member 98 and eccentric portion 98a fitting into the slottedbore 94a of the wedge member 94. Further showing the inclined or beveledsurface of the retaining member 96 upon which the wedge member 94 acts.

The second embodiment allows the shearing blade 88 to be mounted in theblade cartridge 90, thus forming a shearing blade and cartridgeassembly. The shearing blade cartridge assembly is then inserted intothe mounting block 86 and retaining member 96 combination. Theprojection 90a is received on the ledge 86e of the mounting block 86.The eccentric member 98 is then rotated which urges the wedge member 94downward along the inclined surface of the retaining member 96 andlocking the blade cartridge assembly 90 into position. When the bladecartridge assembly needs to be removed, the operator need only loosenthe eccentric member 98, which in turn loosens the wedge member 94,enabling the operator to remove the blade cartridge 90 from the mountingblock 86.

The described mounting arrangements for the shearing blade will be seento provide a firm positive support for the blade throughout itsreciprocal motion used in accomplishing the shearing stroke.Specifically, the described support mechanism for the shearing bladeallows the shearing blade to be quickly and efficiently removed andreplaced in the mounting block.

Although a several embodiments of the invention has been illustrated anddescribed in detail, it will be apparent that various changes may bemade in the disclosed embodiment without departing from the scope orspirit of the invention. Moreover, the terms "vertical" and "horizontal"are used herein in a relative sense and do not suggest any givenorientation of the mechanism described and placed into actual use.

I claim:
 1. A shearing blade mount for a cut-off die set comprising:aplaten; a mounting block adapted for mounting to said platen, saidmounting block having front and rear members separated by downwardopening gap; a shearing blade cartridge including a back plate and clampmember adapted to sandwich a shearing blade therebetween; a shaftmounted to one member of the mounting block; eccentric means mounted tosaid shaft; wedge means mounted to said eccentric to selectively contacta face of the shearing block cartridge thereby locking said bladecartridge in the mounting block.
 2. The shearing blade assembly asdefined in claim 1 wherein a retaining member projects outward on theblade cartridge;a notch located on the complementary bearing surface ofthe mounting block engages the retaining member to lock to furthersecure the blade cartridge within the mounting block.
 3. The shearingblade assembly as defined in claim 2 wherein the shearing blade assemblyincludes a means for fixing the shaft in a said position.